Place one sheet of nori on the sushi mat. Add rice in the middle of the sheet nori. Press rice into a thin layer leaving a small margin on the far side of the sheet nori. Add fully cooked and chopped chicken, red bell pepper, and scallions in the middle. Roll the nori using the mat. Cut the roll in half, then cut each half in half, and then in half again. Serve with wasabi, soy sauce, and ginger. Enjoy your meal!!!